Switch-key.



No. 814,277. I PATENTED MAR. 6, 1906. E. B. CRAFT. SWITCH KEY.

APPLICATION FILED DEO.7, 1904.

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v UNITED STATES PATENT OFFICE.

EDWARD B. ORAF",.OF CHICAGO, ILLINOIS, ASS-IGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF 7 ILLINOIS.

SWITCH-KEY.

Patented March 6, 1906.

Application filed December 7, 1904. Serial 110.285.5351.

To all whom it may concern.-

Be it known that I, EDWARD B. CRAFT, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Switch-Keys, of which the following is a full, clear, concise, and exact description.

My invention relates to a switch-key, and has for its object to provide an improved device which will be especially ada ted for use in telephone exchange switch cards and which will be compact, durable, efficient in operation, and very simple and cheap to manufacture. g

I will describe my invention by reference to the accompanying drawings, wherein- Figure I is a plan View of a number of keys embodying my invention mounted side by side. i'ig. .2 is a side elevation of the switchkey of my invention, and Fig. 3 is a vertical sectional view thereof.

' The same letters of reference are used to designate the same parts wherever they are shown.

The upper frame-platen of the key carries a U shaped supporting-plate b, which is formed of a metal strap, the arms of said supporting-plate being secured to the bottom of the upper plate a by having their upper ends bent to form horizontally-projecting lugs b I), which may be riveted to the frame-plate a. The ends of the frame-plate, which are in practice secured to the switchboard key-shelf, project beyond the ends of strap 6. Each of the arms b 6 of the supporting-plate carries a set of switch-springs and their insulating strips. Each of said sets of switch-springs is mounted upon the outer surface of itssupport and may comprise a spring 0 and its front and back contact-anvils. The said springs are adapted to be operated by a plunger d, mounted to reciprocate in bearings formed in the frame-plate a and in the base of the U-shaped supporting-plate b. The springs c extend beyond the base of the plate I) and are bent inward, as shown, so as to be engaged by a wedge (1, carried upon the end of the shaft (2*, which, as shown, lies between the two arms of the supporting-plate I), a'

push-button d being mounted upon the upper end of said shaft for operating the same. I

It will thus be seen that the'supporting-plate 0 serves the double function of supporting the switch-springs and of furnishing a bear-' ing for the shaft (1 of the'plunger.

A helical s ring a maysurround a portion of the shaft 2 above the frame-plate a, said spring lying between the push-button d and the upper frame-plate a. The said spring serves to insure the return of the plunger to its normal position when released from its depressed position. T 0 limit the downward movementof the plunger, a collar f may be loosely mounted upon the shaft (1 with its lower end resting against the frame-plate a, said collar, as shown, surrounding and pro tecting the spring e.

I employ metal punchings for the plates a b, and I am thereby enabled to make very cheaply a switch-key that is durable and reliable in operation, the minimum amount of work and material being required.

A number of switch-keys such as above described may be very compactly mounted side by side (see Fig. 1) upon the key-shelf of a telephone-switchboard and associated with the different cord-circuits to connect a source of calling-current therewith. This arrangement is very convenient, since any individualkey may be easily removed and access had to the parts thereof for the purposes of inspection, repair, or adjustment, &c., without in any wise disturbing the neighboring keys.

I claim 1. In a switch-key, the combination with a flat upper metal frame-plate, of a U shaped metal strap forming arms and having horizontally-projecting lugs formed at the upper ends thereof and secured to the bottom of the upper frame-plate, the ends of the plate projecting beyond the ends of the arms of the strap. switch-springs and insulating-strips therefor mounted upon the two arms of said strap, and a plunger for operating said springs mounted to reciprocate in bearings formed in the said upperframe-pl'ate and the base of said strap.

2. In a switch-key, the combination with a .metal upperframe-plate, of a U-shaped "metal stra I forming arms secured at their upper ends/to the bottom of said upper frame-plate, the ends of said plate projecting beyond the ends of the arms of said strap, switch-springs and their insulating-strips mounted upon the arms of said strap, all of said parts being formed of punchings, and a plunger for operating said springs mounted to reciprocate in ends of said sprin s extending below the base hearings formed in said upper frame-plate the base of said strap."

3. In a switch-key, the combination with the upper frame-plate, of a U-shaped supporting-plate having horizontally-projecting lugs formed at the upper ends thereof and fastened to thebottom of the upper frame-plate, the ends of said frame-plate projecting beyond the ends of said U-shaped supportingplate', a switch-spring and its associated contacts supportedbyeach arm of said U-sha ed plate upon the outer surface thereof, the ee of said plate an being turned inwardly, a

shaft ass ing between the 'arms of said U-. :5

shape plate and ada ted to reci rocate in bearings in the upper ame and t 6 base of said U shaped late, and a'wedge carried at the lower end 0 said shaft adapted when the shaft is actuated t'o engage said springs andzo move them.

In witness whereof I hereunto subscribe my name this 17th day of September, A. D. 

